1. Field of the Invention
The present invention relates to a sewage pump, and more particularly to a sewage pump that comprises quad-bearing structures for supporting, multiple gaskets for sealing, epoxy filling material to protect wires, and a moisture-sensor to protect a motor so that the sewage pump is kept stable, durable and efficient at high speed operation.
2. Description of Related Art
A conventional sewage pump comprises single-bearing structure at a shaft end and is sealed with a single gasket so that the shaft has poor supporting strength and the sealing efficiency of the conventional sewage pump is insufficient. Moreover, wires and a motor in the sewage pump are not completely protected.
With reference to FIG. 1, the conventional sewage pump as shown in a cross-sectional side view comprises a motor 1, a main shaft 2, an upper impeller 3, a lower impeller 4, a grinder wheel 5, a top cap 6, an upper bearing base 7, a tube body 8, a wire inlet 9, a lower bearing base 10, a lower base 11 and a vertical bypass 12. In the conventional sewage pump, the motor 1 is the power source to drive the main shaft 2. The main shaft 2 penetrates the motor 1 and has an upper end engaging the upper impeller 3 and a lower end engaging the lower impeller 4 and the grinder wheel 5. The top cap 6 mounts on the zenith of the conventional sewage pump and has an upper inlet 61, an upper impeller chamber 62, an upper outlet 63 and a screw 64 combining the top cap 6 with the upper bearing base 7. The upper bearing base 7 has a rotary seal 71, a bearing 72 and a screw 73 combining the upper bearing base 7 with the tube body 8. The tube body 8 is the middle section of the conventional sewage pump and combines the lower bearing base 10 by a screw 81. The wire inlet 9 is defined on the tube body 8 to allow a wire penetrating therethrough. The lower bearing base 10 has a rotary seal 101 and a bearing 102 and is combined with the lower base 11 by a screw 103. The lower base 11 has a lower inlet 111, a lower impeller chamber 112 and a lower outlet 113 communicated with the vertical bypass 12. The vertical bypass 12 is a tube connecting the lower base 11 and the top cap 6 to communicate with the lower outlet 113 on the lower base 11 and the upper inlet 61 on the top cap 6 respectively at two ends.
With reference to FIG. 2 showing a perspective view of the conventional sewage pump, the top cap 6, the upper bearing base 7, the tube body 8, the lower bearing base 10 and the lower base 11 are arranged from top to bottom to achieve the conventional sewage pump. Combinations between the top cap 6 and the upper bearing base 7, the upper bearing base 7 and the tube body 8, the tube body 8 and the lower bearing base 10, and the lower bearing base 10 and the lower base 11 are achieved by screws. The wire inlet 9 is for entrance of the wire to provide power from outside. The vertical bypass 12 is connected between the lower inlet 111 on the lower base 11 and the upper outlet 63 on the top cap 6 so that sewage can be conducted into the sewage pump via the lower inlet 111, pumped through the vertical bypass 12 and then discharged out of the sewage pump via the upper outlet 63.
According to the above description, the main shaft 2 is simply supported by the bearing 72 on the upper bearing base 7 and the bearing 102 on the lower bearing base 10 respectively at each end so that the supporting strength is insufficient and the motor 1 can not efficiently drive the main shaft 2 and actuate the sewage-treating elements such as the upper impeller 3, the lower impeller 4 and the grinding wheel 5. Therefore, the treating efficiency of the conventional sewage pump is low. Moreover, the wire inlet 9 does not have any protection and the wire is easily damaged so that a broken circuit or a short circuit happens frequently. Additionally, because the main shaft 2 only has two rotary seals 71, 101 attached respectively at the two ends, sealing efficiency is poor and sewage probably permeates into the motor 1 or other driving elements. Without having any monitoring device such as moisture-sensors to signal water leakage and to timely stop the sewage pump, the motor 1 will malfunction.